Big endian machine: It thinks the first byte it reads is the biggest. Little endian machine: It thinks the first byte it reads is the littlest. 举个例子，从内存地址0x0000开始有以下数据 0x0000      0x12 0x0001      0x34 0x0002      0xab 0x0003      0xcd 如果我们去读取一个地址为0x0000的四个字节变量，若字节序为big-endian，则读出 结果为0x1234abcd；若字节序位little-endian，则读出结果为0xcdab3412. 如果我们将0x1234abcd写入到以0x0000开始的内存中，则结果为                  big-endian      little-endian 0x0000      0x12               0xcd 0x0001      0x23               0xab 0x0002      0xab               0x34 0x0003      0xcd               0x12 x86系列CPU都是little-endian的字节序. from:http://blog.csdn.net/NeptuneX/